Most fiber optic endoscopes on the market today are made in a conventional manner wherein they include an elongated body or shaft containing both image fibers and light carrying fibers. The endoscope may also have additional passageways for irrigation and/or for conducting operative or investigative procedures. Sometimes it also will be provided with a steering mechanism for pointing the distal end thereof. Most optical endoscopes are configured in a shape to do one specific examination. For example, one may be a flexible cysto-urethroscope for examination of the lower genitourinary tract. Another may be a bronchoscope for looking into the respiratory tract. Still another may be a flexible hysteroscope for looking into the uterus. Once any of these devices is manufactured, it is locked into that configuration and generally can only be used for the purpose for which it was constructed. In other words, it is not adaptable for other types of examinations. An exception to this is that in rare instances one may use a flexible hysteroscope for looking into the bladder. This is done only because the regular scope is broken or unavailable, or done by mistake. There also is a device now available for looking the nasal sinuses. This is a small flexible scope which has an eyepiece, a steering mechanism for changing direction of the device to allow its manipulation into a sinus opening and a light connector. However, it cannot be used for any other purpose.
Because of the necessity for providing a variety of types and styles of endoscopes, the cost invested in endoscopes can be quite high, inasmuch as they are not interchangeable.
U.S. Pat. No. 2,975,785 to Sheldon discloses an endoscope with spaced segments interconnected by two pairs of cables located on opposite sides of the segments. Each pair of cables has distal ends which extend around pulleys mounted on a common shaft which is attached to a handle for rotating the shaft. The rotation of the shaft will cause one of the pairs of cables to be shortened and the other to be lengthened so as to bend the distal end of the endoscope in the desired direction. With the two pairs of cables and control means, the endoscope can be bent in any desired direction.
U.S. Pat. No. 3,266,059 to Stelle discloses a prestressed, articulated joint having pivotal segments which are moved by cables. Associated springs prestress the joint.
U.S. Pat. No. 3,572,325 to Bazell et al., discloses an endoscope with spaced annular segments having control cables extending from the distal end to the proximal end where the cables are connected to a wobble plate which is pivoted to lengthen and shorten the cables to create appropriate bending of the endoscope.
U.S. Pat. No. 3,605,725 to Bentoy discloses a non-circular catheter having a flexible catheter tip with control members extending along the length of the catheter for controlling the angle of the tip. The control means extend from the proximal end of the catheter and are designed for rapid connection to a control mechanism.
U.S. Pat. No. 3,610,231 to Takahashi discloses an endoscope with a stiff central stay and cables which connect to rotatable elements at the proximal end of the endoscope to alternately lengthen and shorten the cables to deflect the distal end of the endoscope in any direction desired. Again, two pairs of cables are provided which are lengthened and shortened together as an appropriate control mechanism is manipulated.
U.S. Pat. No. 3,799,151 to Fukaumi et al., discloses an endoscope with sections that are pivoted together in series and have wires which can be lengthened and shortened for manipulation of the endoscope to cause bending in any desired direction.
U.S. Pat. No. 4,499,895 to Takayama discloses an endoscope with wires that are lengthened and shortened by means of a motor which rotates in response to movement of a control lever.
U.S. Pat. No. 4,753,223 to Brewer discloses a flexible catheter having a plurality of electrical conductors wrapped about an inner tubular body. An insulating layer surrounds the conductors. Rigid non-conductive rings are adhesively secured at axially spaced locations along the distal end of the probe. A plurality of shape memory titanium-nickel wires extend between adjacent pairs of rings and are electrically connected to a control device and power source. Low current pulses are selectively provided by the control device through one or more of the wires to effect contraction of the heater wires to thereby cause the distal end of the probe to bend in a desired direction.
U.S. Pat. No. 4,834,069 to Umeda discloses a guidable endoscope made up of a plurality of articulated tubular members which have passage means for guide wires along the inner portion thereof through which manipulating wires extend for bending the endoscope in a desired direction and position.
U.S. Pat. No. 4,998,916 to Hammerslag et al. discloses a steerable guide wire or catheter for coronary angioplasty applications. A floppy steerable tip is provided on a steering region at the distal end of the implement and a control device at the proximal end, connected by means of a plurality of axially movable deflection wires, extends through the implement. Manipulation of a control permits deflection of the steering region through a full 360.degree. range of motion about the axis of the catheter.
U.S. Pat. No. 5,005,558 to Aomori discloses an endoscope which has an operating body formed as a flexible insertion tube having a bendable tube part with wires for bending the bending tube part by operating a control knob. The bending tube part includes ring link members which are tubular and are connected by flexible connections at upper and lower or left and right sides thereof, alternately to connect the ring link members with one another in series.
Although each of the previously described devices are suitable for their intended purpose, each is rather complex and not of sufficiently simple construction so as to be disposable after each use. In other words, these devices are of unitary construction, housing both the catheter and steering mechanism in one apparatus, and are very expensive. As pointed out above, separate endoscopic devices must be provided for different procedures. Thus, a very expensive endoscope with a steerable device is required for each endoscopic procedure creating a very high cost in maintaining separate endoscopic instruments for all of the various uses contemplated. Also, since the sheath is relatively inexpensive compared to the cost of many catheters, if the sheath cannot be adequately sterilized to prevent the transfer of disease from one patient to another, it can be thrown away after each use.